All earthquakes
2.9
light
EARTHQUAKE DETAILS

6 km South of Forni di Sotto

46 months ago · 28 Nov, 02:42

A light earthquake, rarely felt by people. At only a few km deep the shaking is felt more sharply at the surface.

Stronger than 98% of Italian events in the past year

Where

6 km South of Forni di SottoEarthquakes in the province of UdineEarthquakes in Friuli-Venezia Giulia

How far away could it be felt?

An estimate of how far people may have felt this quake.

  • up to ~8 km · felt only by some, at rest

The coloured rings on the map below show these distances.

Statistical estimate from the Italian intensity attenuation model (INGV): actual perception depends on geology, buildings and depth. Very shallow events can be felt locally even below the threshold.

Earthquake map

26 events
Magnitude:lightweakmoderatestrong

The energy released

How much energy this quake unleashed, translated into everyday comparisons.

338kgof TNT equivalent
1.4 lightning bolts
M3
A magnitude 3 earthquake releases ×1.4 its energy
M2this quakeM4

Each extra magnitude unit releases about 32 times more energy: an M5 is not "a bit stronger" than an M4 — it is a different league.

Energy estimated with the standard Gutenberg–Richter relation; an average lightning bolt ≈ 1 billion joules. Indicative values.

The race of the seismic waves

Two waves set off from the hypocentre: the faster P wave arrives first with a sharp jolt; the S wave carries the actual shaking.

P waves — the first sharp jolt (~6 km/s)S waves — the strongest shaking (~3.5 km/s)
t ≈ 28 s

Animation sped up ~5× compared to reality.

  • Pordenone
    44 km from the epicentre
    first tremor in ~8 s
    main shaking in ~13 s
  • Udine
    57 km from the epicentre
    first tremor in ~10 s
    main shaking in ~16 s
  • Treviso
    81 km from the epicentre
    first tremor in ~14 s
    main shaking in ~23 s
  • Bolzano
    98 km from the epicentre
    first tremor in ~17 s
    main shaking in ~28 s

Theoretical times with average crustal speeds: real values vary with geology. The gap between P and S waves is what earthquake early-warning systems rely on.

How deep it was born

10 km
shallow
1.1 times the height of Mount Everest

At only a few km deep the shaking is felt more sharply at the surface.

in line with the area average (~9 km)

For the same magnitude, a shallow earthquake is felt much more than a deep one: the energy starts closer to the surface.

What kind of quake is this?

Mainshock

It is the strongest quake of its sequence: so far it has been followed by 11 aftershocks within 30 km. Aftershocks tend to fade in number and strength over time.

Activity in the area right now (30 km radius)
0
last 24 hours
2
last 7 days
7
last 30 days
14 before11 after
this quake
Strongest of the sequence2.9

How often does it happen here?

about every ~40 days

Within 50 km of this epicentre, a magnitude ≥ 2.5 earthquake has occurred on average this often: 106 events in the last 12 years of the INGV catalogue.

An average computed on the recent past: it tells how used this area is to shaking, not when the next quake will come — earthquakes cannot be predicted.

The great earthquakes in this area's history

Almost a thousand years of catalogues: the strongest documented events within ~50 km.

19766.5
Friuli earthquake
6 May 1976 · 39 km from here
IX-XCompletely destructive: most buildings are destroyed.
15116.3
Friuli-Slovenia earthquake
26 March 1511 · 47 km from here
IXDestructive: many buildings partly or fully collapse.
18736.3
Alpago Cansiglio earthquake
29 June 1873 · 27 km from here
IX-XCompletely destructive: most buildings are destroyed.
19366.1
Alpago Cansiglio earthquake
18 October 1936 · 34 km from here
IXDestructive: many buildings partly or fully collapse.

Source: Parametric Catalogue of Italian Earthquakes CPTI15 (INGV, CC BY 4.0).

The closest seismic structure

Tramonti-Montemaggiore

The epicentre lies about 8 km from Tramonti-Montemaggiore, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 6.2between 1 and 6 km deep

Faults are mapped to build better and understand the territory: knowing them says nothing about when an earthquake will occur, which remains unpredictable. Source: DISS 3.3 (INGV, CC BY 4.0).

Other quakes in the area

1.4
4 km West of Barcis
18 km South-West · 10 km
46 months ago
26 Nov, 12:59
0.6
2 km North of Verzegnis
25 km East · 11 km
45 months ago
2 Dec, 20:57
0.9
2 km East of Lauco
27 km East · 12 km
46 months ago
22 Nov, 05:22
1.3
3 km South-East of Lauco
27 km East · 13 km
46 months ago
21 Nov, 06:47
1.0
4 km West of Barcis
18 km South-West · 10 km
46 months ago
21 Nov, 01:22
0.3
4 km South-West of Tolmezzo
30 km East · 14 km
45 months ago
5 Dec, 04:58
0.8
45 months ago
9 Dec, 16:33
0.8
3 km North-West of Raveo
21 km North-East · 6 km
46 months ago
15 Nov, 17:37
1.0
2 km South-East of Preone
20 km East · 11 km
46 months ago
15 Nov, 11:29
1.1
46 months ago
14 Nov, 20:57

Data: INGV — National Institute of Geophysics and Volcanology (CC-BY 4.0)

Estimates computed by Meteare on INGV data (Gutenberg–Richter relation; Italian macroseismic intensity attenuation model).

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